More than one-third of patients with type 2 diabetes eventually require treatment with insulin to control blood glucose levels as the severity of diabetes worsens and oral drugs lose their effectiveness. Some oral medications (the sulfonylureas, metformin and the thiazolidinediones) are also being prescribed with increasing frequency in combination with insulin. All insulins were isolated from beef or pork pancreases until 1982, when techniques became available to produce human insulin. Only human insulin and its biosynthetic modifications are manufactured today. Three types of insulin are available: rapid-, intermediate-, and long-acting. Typically, a combination of insulin types is used to treat diabetes. The dose and mixture of insulin used, as well as the frequency and timing of injections, vary from patient to patient based on such factors as age, weight, eating habits, exercise and blood glucose levels. Insulin schedules will continue to be adjusted, when necessary, throughout life; for example, less insulin may be needed when a person begins an exercise program, more during periods of illness or psychological stress. To be effective, insulin must be injected. It cannot be swallowed, because digestive enzymes would destroy the insulin before it reached the bloodstream. Injections are given subcutaneously (under the skin) at any site where there is fatty tissue, for example the abdomen or the front and outer side of the thigh. A needle and syringe are most often used for insulin injection. Other methods include insulin pens and jet injectors. Another option for insulin administration is continuous subcutaneous insulin infusion (CSII), which involves the continuous delivery of insulin by an external pump, usually worn on a belt. The insulin passes through tubing (a cannula) beneath the skin of the abdomen via a needle, which the person changes every few days. The continuous insulin infusion, supplemented with additional doses of insulin through the pump with each meal, promotes excellent control of type 1 diabetes while limiting the number of needle sticks to one every two to four days. Some people with hard-to-control type 2 diabetes may also benefit from using the pump. Last Updated: 7/7/2003
The Johns Hopkins University 1996-2003. All rights reserved. This information is not intended to provide advice on personal medical matters, nor is it intended to be a substitute for consultation.
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